Front projection screens, also referred to as reflective- or reflection-type projection screens, are widely used in cinemas, home theaters and other consumer and commercial applications, wherein a projector is on the same side of the projection screen as the viewer(s).
In designing a front projection screen, it may be desirable to provide high brightness, an acceptable viewing angle (light distribution), color rendition and/or contrast. Many screen designs have been developed that can improve projected image quality over a simple “white wall”.
Front projection screens that are used in cinema or home theater applications generally are viewed in dark or subdued lighting conditions. Accordingly, many commercially available screens may lack an ability to effectively reduce or eliminate ambient light reflection that produces loss of contrast and causes the image to wash out in brightly lit settings. One approach to improve the effective contrast of a front projection screen is to increase its gain, or on-axis brightness. High gain can provide a larger ratio of reflected image light to reflected ambient light in a given setting. This may perceived by the viewer in a number of ways, including brighter whites, deeper blacks, more pleasing color saturation, improved edge definition and/or improved picture detail.
Unfortunately, high gain screens may reduce the viewing angle of the screen. Stated differently, high on-axis brightness may be achieved through reduction and brightness at other angles. Thus, for a given projector with a given lumen output, a high gain screen may have a smaller field of view than a low gain screen. In order to allow a relatively wide field of view, many commercial projection screens offer only a modest increase in gain over a white wall.
U.S. Pat. No. 6,724,529 to Sinkoff, entitled “Reflection-Type Projection Screens”, describes a projection screen comprising; a substrate having a generally flat forward surface; a diffusion layer formed of a plurality of generally equally spaced apart concave features forming micro lenses; a layer of reflective material deposited on a rearward facing surface of the diffusion layer; the diffusion layer laminated to the forward facing surface of the substrate so that the layer of reflective material is sandwiched therebetween. See the abstract of U.S. Pat. No. 6,724,529.